haberg@matematik.su.se (Hans Aberg)
wrote:>[The problem with 1970s extensible languages wasn't that they didn't work,>it was that adding more syntax on the fly didn't solve any real problems,>and I don't think that's changed. Overloading like C++ and TeX provide>seems a lot more promising. -John]

Quite on the contrary:

C++ function name overloading has already reached its limits for
usefulness, and people are craving for more function names. (I have
worked a bit on this question.)

And TeX is pretty much an obsolete program, only surviving because of
it heritage. But due to the limitations of TeX, unable to handle
different syntaxes properly, developers, like that one the LaTeX3
project, are spending a lot of time trying to work around it. In fact,
the LaTeX3 project is built up around programming principles that are
not implementable in TeX as such; one then tries to find a good
approximation.

Just adding more syntax on the fly does not solve any problems though; one
must have a good idea of how it might be used.